Measurement of Altered A beta PP Isoform Expression in Frontal Cortex of Patients with Alzheimer%26apos;s Disease by Absolute Quantification Real-Time PCR

作者：Tharp William G; Lee Yong Ho; Greene Shane M; Vincellete Elise; Beach Thomas G; Pratley Richard E^*

来源：Journal of Alzheimer's Disease, 2012, 29(2): 449-457.

DOI：10.3233/JAD-2011-111337

• Alternative splicing
• Alzheimer%26apos
• s disease (AD)
• amyloid-beta (A beta)
• amyloid-beta protein precursor (A beta PP)
• dementia
• kunitz
• polymerase chain reaction

Enzymatic cleavage of amyloid-beta protein precursor (A beta PP) produces amyloid-beta (A beta) peptides which form the insoluble cortical plaques characteristic of Alzheimer%26apos;s disease (AD). A beta PP is post-transcriptionally processed into three major isoforms with differential cellular and tissue expression patterns. Changes in A beta PP isoform expression may be indicative of disease pathogenesis in AD, but accurately measuring A beta PP gene isoforms has been difficult to standardize, reproduce, and interpret. In light of this, we developed a set of isoform specific absolute quantification real time PCR standards that allow for quantification of transcript copy numbers for total A beta PP and all three major isoforms (A beta PP695, A beta PP751, and A beta PP770) in addition to glyceraldehyde-3-dehydrogenase (GAPDH) and examined expression patterns in superior frontal gyrus (SFG) and cerebellar samples from patients with (n = 12) and without AD (n = 10). Both total A beta PP and A beta PP695 transcripts were significantly decreased in SFG of patients with AD compared to control (p = 0.037 and p = 0.034, respectively). A beta PP751 and A beta PP770 transcripts numbers were not significantly different between AD and control (p %26gt; 0.15). There was trend for decreased percentage A beta PP695 (p = 0.051) and increased percentage A beta PP770 (p = 0.013) expression in SFG of patients with AD. GAPDH transcripts levels were also decreased significantly in the SFG of patients with AD compared to control (p = 0.005). Decreasing total A beta PP and A beta PP695 copy number was associated with increased plaque burden and decreased cognitive function. In this study we describe a simple procedure for measuring A beta PP isoform transcripts by real-time PCR and confirm previous studies showing altered A beta PP isoform expression patterns in AD.

• 出版日期2012